Does x86 have an atomic increment that keeps the value that was stored?

Question

I have found lock inc addr but that doesn't keep a copy of the stored value around and even a read immediately after it in the same thread could come after a competing write.

The best solution I have found is a load/inc/cas loop.

Answer 1

lock xadd is your friend.

Answer 2

see atomic_impl.h for more x86/x86_64 atomic primitives and usage.